Office to housing conversion: estimating life cycle environmental and financial performance

The document titled "Office to housing conversion: estimating life cycle environmental and financial performance" was published in the Journal of Physics: Conference Series by a group of authors including D Stiernon, A Böhlke, A Stephan, M Bos, and G Marino. This research addresses the increasing challenge of converting office buildings into residential spaces, particularly in urban settings like Brussels, where the trend has been growing since the early 1990s.

The research aims to quantify the life cycle greenhouse gas emissions and financial performance associated with various scenarios for repurposing office buildings. These scenarios include renovating the building as an office, converting it into residential use, and comparing these to demolition and reconstruction options for both purposes. This study is particularly relevant as cities across Europe seek sustainable solutions to housing shortages exacerbated by the COVID-19 pandemic.

A case study approach was utilized, focusing on a representative office building located on rue d'Arlon, Brussels. The building, constructed in the 1960s and vacant for nearly 20 years, covers approximately 11,000 m². The study evaluated four main scenarios: (1) renovation as an office, (2) conversion into housing, (3) demolition and construction of an office, and (4) demolition and construction of a residential building. The research employed the TOTEM tool to quantify greenhouse gas emissions, focusing on climate change indicators. This tool was chosen for its alignment with European standards and its capability to analyze the environmental impacts of construction materials.

The results indicate that demolition and construction scenarios have the most significant environmental impacts. The office renovation scenario demonstrated the lowest environmental impact, accounting for only 13% of the emissions from the housing demolition scenario. The study found that the differences in environmental performance between offices and residential buildings are not as pronounced as anticipated, largely depending on specific assumptions made during the analysis. From a financial perspective, the study highlighted how the real estate market favors demolition and construction due to tax advantages, enabling VAT recovery and maximizing property value. The financial analysis showed that the total cost of renovations with a change of use did not significantly differ from new constructions, ranging between €1,800 and €2,200 per square meter. Notably, converting office spaces into residential units was deemed less financially attractive due to various complexities and market conditions.

The findings stress the importance of understanding both environmental and financial factors in urban planning. They reveal that while converting offices into housing may seem beneficial from a sustainability viewpoint, financial motivations often lead developers to prefer new office constructions. The study concludes that without policy changes or incentives, the trend of converting office spaces into affordable housing may not meet the urgent needs of urban populations.

This research offers critical insights into the life cycle environmental and financial performance of office-to-housing conversions. It serves as a benchmark for future projects and encourages further examination of strategies to enhance the sustainability of urban housing while considering market dynamics and environmental impacts.